A vast number of assemblies include interconnecting tubes, and many of these interconnecting tubes are those in which a second tube interconnects with an outer wall of a first tube and extends transverse to a first tube.
One exemplary assembly that can include interconnecting tubes is a heat exchanger. A heat exchanger is a device which transfers the heat of one substance to another (i.e., from a warm or hot surface to a cold or cooler one) such as evaporators, condensers, and radiators. A conventional vapor compression system typically includes two heat exchangers, an evaporator and a condenser. Some vapor compression systems further include a receiver dryer which is intended to perform some or all of the following functions: filtration and/or dehydration of refrigerant, compensation for variations in its volume, and separation of the vapor and liquid phases of the refrigerant. Typically, a fluid inlet tube (i.e., a second tube) extends from an outer wall of a condenser header (i.e., a first tube) and is coupled between an upstream section of the condenser header and an inlet port of the receiver for carrying vapor and liquid phases of refrigerant to the receiver dryer. A fluid outlet tube extends from the outer wall of the condenser header and is coupled between an outlet port of the receiver and a downstream section of the condenser header (i.e., the first tube) for returning liquid phase refrigerant to the downstream section.
Many assemblies, including condenser systems used in vehicle air conditioning systems, are typically manufactured by first assembling brazing clad components together, then passing the assembled components through a brazing furnace to braze, or fuse, the components together. In condenser systems, typically one or more brackets are used to mount the receiver dryer, inlet tube, and outlet tube to a header of the condenser. The bracket or brackets may be first bolted or tack welded to the header prior to the brazing process.
Various techniques have been employed for connecting the inlet and outlet tubes to the condenser header. For example, the inlet and outlet tubes and the receiver dryer may be bolted to the brackets and/or tack welded into place prior to brazing. As such, the inlet and outlet tubes and the receiver dryer can be fused with condenser system during brazing. Unfortunately, bolting and tack welding prior to brazing is typically performed manually, thus resulting in undesirable labor costs for the manufacturing process.
In order to avoid the problems associated with bolting and/or tack welding prior to brazing, other prior art techniques include a specially shaped opening in an element and/or a specially shaped mating end of a tube to be inserted into the element. For example, the tube end may include a transversely extending peg and the opening may include a notch for passage of the peg so that during brazing the tube can be held temporarily in the opening by the peg after the tube has been rotated in the opening. Unfortunately, such a structure calls for the incorporation of a separate, and undesirably costly, process in both the tube and header to fabricate the notch and the peg. In another scenario, the tube end is specially shaped to include a protuberance, or spout, that holds the tube temporarily in the opening prior to being soldered together. Such a structure calls for relatively complex manufacturing of the protuberance. In addition, due to the protuberance, the tube must be inserted at an angle greater than perpendicular to the element to which it is being coupled, making assembly more difficult and causing an undesirably loose fit between the tube and the opening.
Alternative to the above pre-braze techniques, the inlet and outlet tubes and the receiver dryer may be coupled to the brackets and to the header following the brazing process via threaded connections, connecting sleeves, or press fitting. While these prior art techniques may be generally satisfactory, such techniques call for an undesirably high number of discrete components. The undesirably high number of discrete components increases the likelihood that the system will be misassembled, increases the potential for damaging the inlet and outlet pipes coupled between the condenser and the receiver dryer, and increases the likelihood of fluid leakage. In addition, the post-braze manual assembly again results in undesirable labor costs for the manufacturing process.
Thus, what is needed is a technique that enables simple, secure, cost effective, and convenient fixation of a first tube to a second tube, and more specifically, the fixation of the inlet and outlet tubes to a condenser header.